Thanks to information and advice provided by people on the DISboards I recently successfully 're-shopped' a reservation whilst onboard, saving some money and gaining some OBC. However, my own advice to anyone planning to do this is to make sure you have correct and up-to-date cost information with you otherwise you may not get the best deal. I booked a Southern Caribbean cruise on opening day direct with DCL online. I kept checking prices right up until the day before our recent cruise and the price had increased slightly. I took details of that price with me when I visited the Future Cruise desk and am very glad that I did. The CM at the desk was very helpful; he made a new reservation for us, then swapped the rooms so we stayed in the same one, and noted our TA on the reservation; then cancelled the original reservation. BUT he quoted me 2 different (higher) prices before I got the one which I had seen online only the day before. The first price he quoted was far higher, obvious to me even without checking my notes that it was too high; it was about $500 more than our original price and that was supposedly with the 10% discount. The second price was still too high but if I hadn't checked prices and made a note of them, I might have been caught, thinking it was due to price increases since opening day. When he quoted the second price I checked my notes and told him the exact figure I had seen online the day before. Which he then matched, then deducted the 10% discount, and I only paid a 10% deposit. (My original 20% deposit was refunded to my credit card.) I don't know what the problem was and, as I said before, the CM was extremely helpful. But I just wanted to warn anyone planning to 're-shop' or, indeed, make any onboard booking, to do some research beforehand and have the figures with you to make sure that you do get the best deal.